The recent developments in the experimental realization of quasi-one-dimensional (1D) systems exhibit many interesting features. These include current quantization which has the potential application for a current standard as well as quantum information and security schemes. In this paper, we investigate the effect of spin-orbit interaction (SOI) on the energy levels of electrons confined to quantum dots on the surface of nanotubes. The radius of a nanotube is a few nanometers and is quasi-1D. The energy levels play a crucial role in determining the electron transport properties.The SOI may arise from the electrostatic confining potential due to gates applied perpendicular to the axis of the nanotube. The quantum computation scheme which we are suggesting consists of a nano-circuit of nanotubes on which electrons are confined within dots. The qubit operation is based on the exchange interaction between a pair of spins occupying states within the quantum dots. We employ a simple model for the electron confinement to obtain the energy eigenstates. Our simplified calculation was able to show that the SOI splits the energy levels which are then used to obtain the exchange energy of a pair of spins with the s-wave Heitler-London approach. We calculate the exchange energy of the entangled electrons on a pair of coaxial and parallel nanotubes as a function of separation between the nanotubes and show that the SOI enhances the entanglement.

Date Published: 12 May 2006
PDF: 9 pages
Proc. SPIE 6244, Quantum Information and Computation IV, 62440B (12 May 2006); doi: 10.1117/12.664025

Published in SPIE Proceedings Vol. 6244:
Quantum Information and Computation IV
Eric J. Donkor; Andrew R. Pirich; Howard E. Brandt, Editor(s)